People involved at OAB: de Ruiter, Stirpe.
The Westerbork Northern Sky Survey has mapped the sky (above declination ) at 325 MHz (and is complementary to the NVSS survey at 20 cm made by the VLA). The overall catalogue contains about 200000 radio sources with flux density above 15 mJy. Work is in progress at the Bologna Observatory to extract from the WENSS catalogue all radio sources associated with ``bright'' (i.e. ) galaxies. All automatic procedures used in the extraction process have now been tested, and a preliminary list of about 4000 WENSS bright galaxies is available; the final list is expected to be available by the end of 2004. Several spin-off programmes are in progress: a number of possible relic radio sources (characterized by a steep radio spectral index) were selected for further study with the VLA at different frequencies. The new information on the radio structure and the spectral index confirms that two of the three sources are indeed fossile sources, while the third is a fossile source in which the radio activity has restarted.